Ted gets to know Cindy (Rachel Bilson), a student (PhD Candidate) who is close to his own age. Barney, meanwhile, tries to pick up a hot bartender who hates guys in suits by wearing casual clothes. [6]

After quitting cold turkey, Marshall takes up smoking again, with Lily, Ted, Robin and Barney not far behind.

Maggie (Joanna Garcia) a girl next door that Ted has wanted to date for years has suddenly broken up with her latest boyfriend, giving him and many other guys a chance to score with her.

The gang celebrates Thanksgiving this year with Lily’s estranged father (Chris Elliott) whom she hadn’t spoken to in three years. Ted and Robin are given the chance to use Marshall’s fourth Slap Bet slap on Barney.

Barney pulls out all of his greatest tricks to reenter the dating scene after he and Robin break up.

A major crisis in Barney and Robin’s relationship gives Lily ideas on how to break them up with Alan Thicke’s help.

Barney, thinking he and Robin are the perfect couple, gives relationship advice to Marshall, which turns out to be a big mistake.

Ted proposes a road trip with Marshall to their favorite pizza parlor in Chicago to reminisce their bachelor days, but Lily wants in on the trip. Barney is seeking US citizenship for Robin, but her Canadian traits still remain.

Marshall and Lily desperately try to have a double date with Barney and Robin. Girls suddenly appear at Ted’s apartment just to find a place to sleep in, making him a "Sexless Innkeeper."

When Robin fears that Barney is cheating on her, she soon discovers that he is spending his evenings with Ted learning everything there is to know on how to date her.